A plurality of the electrical contacts or contact pins are frequently mounted in an insulative male connector housing, with one end of the contacts extending from the connector housing so as to make mechanical and electrical contact with a female mating connector. In a typical header, contacts or wire pins which normally have a circular or square cross section are staked into round holes in a housing. Retention of the pins in the housing is generally achieved by a press fit between the contact pins and the holes of the connector housing. The contact pins are typically made from bronze, brass, steel, stainless steel, copper alloy or other electrically conductive material and the connector housing is typically made from a plastic or resin type nonconductive material. During the staking process, the holes of the connector housing can become enlarged and deformed due to the negative clearance between the pin, and the perimeter of the holes. This degrades the ability of the connector housing to securely hold the contact pins in their proper position and alignment.
It is known to provide recesses and projections on the longitudinal side surface of contact pins to form a retention portion on the contact pins. These retention portions provide holding power when the contact pin is inserted into a connector housing. The recesses and the projections may be formed by stamping technology in which the projections are forced or extruded outwardly as the recesses or grooves are stamped into the retention portion of the contact pin.
In one known embodiment, the projections of the contact pins are formed by striking the diameter of the contact with chisel-like tools on different sides at the same time (e.g. two or more sides). This action causes four “V” shaped depressions to be produced in the contact. Between the depressions, the projection is raised above the original diameter of the contact. This enlarged portion of the contact pin is used to provide increased press fit between the contact pin and a hole of a connector housing.
Even with the utilization of these known retention sections, the connector industry is plagued by defective connectors due to inadequate retention of the contact pins in their connector housings. Many problems occur in connectors due to loose contact pins. These pins may fall out or move partially out of their intended position causing mechanical and/or electrical failure. Past solutions that have been proposed to solve this problem have included increasing the amount of press fit between the holes of a connector housing and the contact pins. This is accomplished by making the projections larger or the hole smaller. However, this approach has not been effective because it has caused cracking or warpage of the connector housing.